At least 1,000 Iranian marines have reached Syria and joined the Russian forces to fight the Syrian rebels, a Jerusalem-based military intelligence website has reported.

DEBKAfile reported on Friday that elite troops of the Iranian Revolutionary Guards Corps (IRGC) arrived at the military air facility in Ghorin, located south of Latakia, a Syrian port city.

After being banned by the US and and other NATO members from using their airspace, Russia reportedly found a circuitous route via Iran to deliver weapons to the Syrian Mezze Airbase in Damascus, it is reported.

Russia apparently took the air route over the Caspian Sea that runs through northern Iran and Iraq to reach its ground base in Syria in Jablah, where, in the coming days, the country will be sending military reinforcements to "save the Syrian ruler Bashar Assad," the Israeli military report noted.

The Iranian soldiers have now "hooked-up" with the "just arrived" Russian forces in Jablah, a base built by the Russians outside Latakia.

Iran, however, has maintained that its marines are in Syria to assist the Hezbollah in Zabadani. The Israeli media report citing sources on ground said that Iran's main intention is to strengthen its base in Ghorin, with Russian support.

Russia Strengthens its Jablah base

Russia, in recent days, has expedited efforts to reinforce its base in Jablah. As part of its military aid to Syria, Russia will be deploying advanced S-300 air defence missile systems in the base, where combatant units from Russian Marine Brigades 810 and 336 will also be housed.

A Russian MiG-31 interceptor craft also has bee put on standby at the Mezza airbase at Damascus airport to offer air support to the combined Russian-Iranian forces.

A Russian nuclear submarine, Dmitri Donskoy TK-20, is also in Syria as part of the effort to stop Syrian rebels and Islamic State (Isis) from gaining ground in northern Syria.